The present invention pertains to a temperature control system for a motor vehicle, comprising an air-conditioning device with a compressor device for compressing a working medium of the air-conditioning device.
In modern motor vehicles, especially in utility vehicles, there is increasing demand for temperature control systems that are also able to produce pleasant climatic conditions or pleasant temperatures in a vehicle interior or a driver""s cab. Thus, providing parking heaters, by means of which sufficient heating is possible even when the vehicle is at a standstill, has become known. Above all, at high outside temperatures, there is also an increasing demand to provide for cooling when at a standstill, i.e., e.g., if the driving motor of the vehicle is not running, i.e., to make possible a so-called parking cooler or air-conditioner. In this regard, e.g., systems have become known, in which an additional internal combustion engine drives a compressor of an air-conditioning device in order to obtain the necessary flow of working medium in the manner of storage space cooling systems.
The object of the present invention is to provide a temperature control system for a vehicle, which, with a simple structural design, is additionally able to provide the function of a parking cooler.
According to the present invention, this object is accomplished by a temperature control system for a vehicle, comprising an air-conditioning device with a compressor device for compressing a working medium of the air-conditioning device, whereby the compressor device can be driven by a first drive unit, preferably the driving motor of a vehicle, and/or a second drive unit, whereby the second drive unit comprises a Stirling motor.
Thus, in the temperature control system according to the present invention, it is provided that the compressor device providing for the circulation of the working medium of the air-conditioning device can be operated both by the driving motor of a vehicle, as is usual in conventional vehicle air-conditioning systems, and, as an alternative or in addition, can also be driven by a special drive unit, namely a Stirling motor. This Stirling motor is put into operation if the function of vehicle interior air-conditioning is desired, but at the same time, e.g., the driving motor of the vehicle shall not be operated. A considerable advantage of this is that such Stirling motors have a comparatively simple design with very long operating life and low noise generation.
In order to be able to provide the temperature differences necessary for the operation of a Stirling motor, it is suggested according to an especially advantageous aspect of the present invention that a fuel-operated heater be assigned to the Stirling motor for providing a heating medium for heating a hot area of same. The combustion products produced in this heater may then be used as the heating medium for heating the hot area. It is especially advantageous in this embodiment that it is then also possible to feed a heating heat-exchanger device provided in a vehicle, which, e.g., otherwise takes up heat from a coolant of the vehicle engine for heating the vehicle interior, with the heating medium and thereby to heat the air flowing through the heating heat-exchanger device. The heater to be provided according to the present invention may thus be used both for the air-conditioning, i.e., cooling operation, namely as an energy source for the Stirling motor, and for the heating operation, namely as an energy source for the heating heat exchanger.
Moreover, in order to be able to obtain the temperature differences mentioned above for the Stirling motor, it is suggested that a cooling medium circulation is assigned to the Stirling motor for feeding a cooling medium to a cold area of same. It is especially advantageous if the cooling medium is the coolant of the driving motor of a vehicle. In this case, the driving motor of the vehicle may thus be used as a means for lowering the temperature, in which the cooling medium heated in the Stirling motor discharges heat and thus can again be led to the Stirling motor with a reduced temperature.
In an especially advantageous embodiment of the present invention, it is suggested that the compressor device comprises a first compressor that can be driven by the first drive unit and a second compressor that can be driven by the Stirling motor. Thus, two compressors, which are also structurally separate from one another, are present, which can each be mounted in a vehicle in areas that are especially advantageous for this.
In order to be able to then selectively use one of the compressors in such an arrangement to produce the compressed state of the working medium of the air-conditioning device, it is suggested that a valve array be provided, by means of which the first compressor or the second compressor can be selectively switched on in the working medium circulation.
The Stirling motor to be used in the system according to the present invention may be designed as a free-piston Stirling motor. Such free-piston Stirling motors have a very high efficiency and thus are especially preferred for preventing excessive energy losses.
According to another aspect of the present invention, the object mentioned in the introduction is accomplished by a temperature control system for a vehicle, comprising an air-conditioning device with a compressor device for compressing a working medium of the air-conditioning device, whereby the compressor device can be driven by a drive unit comprising a Stirling motor.
The idea that was already described above of using a Stirling motor as a drive for a compressor of a temperature control system or of the air-conditioning device of same can also be put into practice if this Stirling motor is essentially the only drive source and insofar as, regardless of whether or not the driving motor of the vehicle is put into operation, the air-conditioning device is always operated using the Stirling motor.
The present invention is described in detail below with reference to the attached drawings based on preferred embodiments. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.